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96601
From: eaamon, [DNS_Address]
Subject: question of route 92 SF bay area
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I have a question about the picture I saw this morning on the closed road. route 92 San Mateo if I remember right, was listed as closed indefinitely had a large sink hole. that route goes over the SAF (San Andreas Fault) at the end of lake San Andreas. hence it's fault name sake. I am not in the area or I would go to view it's location. question I have. id it right at the fault line or just near it? it probably does not matter. the East Bay has had a few recent shakers to move the area some what along. rains and recent waters may have helped it to move and open the hole. what is next,,, teotwawki sink holes opened up near the new Madrid MO area before it went. my EX said there were others in CA too and not just a mud slide. |
96602
From: pamela, [DNS_Address]
Subject: Re: question of route 92 SF bay area
URL: https://abc7news.com/bay-area-sinkhole-highway-92-closed-storm-damage-half-moon/12693486/
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heres the news report and it mentions 2 sinkholes, maybe you can deduce its location from the report. |
96603
From: Redhart, [DNS_Address]
Subject: Re: question of route 92 SF bay area
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Crystal Springs Reservoir --what is called a "sag lake)--as it's created by the sag in the crust that overlays the San Andreas fault, is a mile and a half (roughly) east of this sink hole..the sink hole is higher up on the ridge on the road above the lake. I've been on this road many times, and it pretty much runs the ridgetop. The sink hole (s) is not "on" the San Andreas fault, but above it on high ground (near as I can tell, anyway).. Since this is the peninsula, everything is "relatively" close to the fault. Most likely--drainage underneath washed out (the most common reason in Calif for these things)--maybe a busted drainage pipe or something? Would be difficult to disern the exact cause without investigation at the scene. That's a pretty deep, straight-sided hole..as if the gopher from hell has been at work. It's not like in Florida where everything is underlain by limestone that can eat out from beneath by water over millions of years. There is very little limestone on the peninsula. It's mostly sedimentary accretions..clays and jaspers and ancient ocean floor scrapings piled up by the San Andreas to form the coastal mountains. |
96627
From: eaamon, [DNS_Address]
Subject: Re: question of route 92 SF bay area
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from what I can see I'm not sure if related. I also did see that 92 was closed just West of Skyline Blvd (RTE 35) too as that section was slowly washing down hill as a slow moving slide. that section was closed too. pictures were on one of my news channels. as for being on the SAF that maybe but the proximity is close enough movement from the fault could have opened it up. Lake San Andreas is just NNW of Crystal Springs Res. I do wonder if it sink hole was on the Northern edge of the Rogers fault/Loma Prieta quake fault. tnx Redhart |
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[96628]
96628
From: eaamon, [DNS_Address]
Subject: Re: question of route 92 SF bay area
| https://goo.gl/maps/Eo4QBBnPJhGQGyjU9 |
Responses:
None
96626
From: eaamon, [DNS_Address]
Subject: Re: question of route 92 SF bay area
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the picture shows a large drainage pipe in back of the vehicle. I would guess a drainage issue. |
Responses:
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96615
From: Redhart, [DNS_Address]
Subject: What causes California sinkholes? (NYT article)
URL: https://www.nytimes.com/live/2023/01/14/us/california-weather-storms-forecast
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(Photo above: One sinkhole, at least 50 feet wide and 30 feet deep, parted a street in the suburban Chatsworth neighborhood of Los Angeles.Credit...Mark Abramson for The New York Times) Jan. 14, 2023, 3:52 p.m. ET7 minutes ago 7 minutes ago Adeel Hassan Why are the California storms causing sinkholes? While they looked like craters caused by a celestial body, the fresh scars that pockmarked the waterlogged landscape of California this week instead sprung up from the earth. One sinkhole, at least 50 feet wide and 30 feet deep, parted a street in the suburban Chatsworth neighborhood of Los Angeles and swallowed two cars along with concrete chunks on Monday; another one damaged 15 homes in Santa Barbara County; farther up the coast, a colossal chasm, caused by a collapsed culvert, forced the Oakland Zoo to close until next month. Most sinkholes in the United States occur naturally, but they are not common in California because the state’s surface was not shaped by dissolving bedrock. Pictures of cars and homes falling into the ground across California are usually associated with earthquakes, not sinkholes. But the relentless parade of atmospheric rivers since December has changed the state’s geological imagery. “With more heavy rain in the forecast, the erosion will continue and there are no doubt structures that are being impacted that will collapse,” said Randall C. Orndorff, a research geologist for the U.S. Geological Survey, in an interview on Friday. The sinkholes were created when torrents of water rushed into man-made underground layers, like road drains, water mains, sewers and culverts that carry streams or open drains under roads. “When you get all that rain that fast, it doesn’t even have time to seep into the ground,” Mr. Orndorff said. The overflow water churned and formed pockets of space, or found other voids to fill and widen. The collected water weakened the ground supporting the surface above, making it more prone to collapse. Above ground, the thoroughly drenched top layer also struggled under the extra water weight. “We do believe that these events are becoming more frequent as the nation’s infrastructure is aging,” Mr. Orndorff said. Naturally occurring sinkholes, though, can appear just about anywhere. Unsurprisingly, they are most frequent in regions with rock that is soft and dissolves easily, like limestone. Sinkholes are also more common near salt beds, natural springs and caves. Nearly 20 percent of the contiguous United States has this type of soluble bedrock, according to the Geological Survey. Sinkholes are most common in Florida, Texas, Alabama, Missouri, Kentucky, Tennessee and Pennsylvania. They can devour cars, homes, buildings and roads while causing millions of dollars in damage. Sinkholes can also occur wherever there is heavy precipitation and are largely undetectable from the surface, but cracks in a home’s foundation or sagging parts of a yard may be warning signs, Mr. Orndorff said. “It’s very localized, he said, “and that’s what makes it difficult to predict.” |
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